Dolichorhynchops

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Dolichorhynchops Fossil range: Late Cretaceous
Conservation status
Extinct (fossil)
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Sauropsida Superorder: Sauropterygia Order: Plesiosauria Suborder: Plesiosauroidea Family: Polycotylidae Genus: Dolichorhynchops Species: D. osborni D. herschelensis

Dolichorhynchops is a genus of Polycotylid Plesiosaur from the Late Cretaceous of North America, containing two species, D. osborni and D. herschelensis.

[edit] D. osborni

D. osborni was the first species in the genus to be described, in 1903.

[edit] D. herschelensis

D. herschelensis was described as a new species in 2005. It was discovered in the Bearpaw Formation of Saskatchewan, Canada, a Late Cretaceous (late Campanian to Maastrichtian) rock formation. The fossil was found close to the town of Herschel in south-western Saskatchewan, from which the species name is derived. The rock formation it was found in consists of sandstones, mudstones and shales laid down in the Western Interior Seaway, just before it began to revert to dry land.

The type specimen of D. herschelensis was discovered in a disarticulated state (ie the bones were scattered about the discovery site). The skull, lower jaw, ribs, pelvis and shoulder blades were all recovered, but the spine was incomplete, so the exact number of vertebrae the living animal would have had is unknown. All four limbs are missing, with the exception of 9 small Phalanges (finger bones) and a small number of limb bones found close by which may belong to the animal in question. The specimen is believed to be an adult, due to the fusion of certain bones It is also believed to have been substantially smaller than its close relative, D. osborni, as some juvenile specimens of D. osborni are larger than the adult specimen of D. herschelensis. Assuming that only a few vertebrae are missing from the skeleton, the animal is estimated to be about 2.5 to 3 metres in length. The snout is long and thin, with numerous tooth sockets. However, very few of the thin, sharp teeth remain.

[edit] References

Sato, T., 2005. A new Polycotylid Plesiosaur (Reptilia: Sauropterygia) from the Upper Cretaceous Bearpaw Formation in Saskatchewan, Canada. Journal of Paleontology, 79: 969-980.